It is known to bind the free leading and trailing ends of a weft thread into the respective selvage. Reference is made in this connection to European Patent Publications EP 0,291,744 A2 (Henzl et al.) published on Nov. 23, 1988; EP 0,534 429 A1, (Viscardi) published on Mar. 31, 1993; and EP 0 431 484 A1 (Schwemmlein et al.) published on Jun. 12, 1991. Conventionally the cut ends of the weft thread are blown back by respective auxiliary air nozzles into the fabric selvage as it is being formed.
It is a disadvantage in conventional selvage forming devices of this type that the end of the weft thread is merely inserted into the next following loom shed, but it is not fixed during the time of insertion whereby an uneven selvage is formed. This feature of conventional selvage formation techniques is especially undesirable where the fabric has low weft thread densities in the range of, for example 0.5 to 1.5 weft threads per centimeter length of warp yarns. In such situations the weft thread ends have a tendency to unravel again after the insertion as the next shed is being formed. The weft thread ends form undesirable loops if they partially escape from being bound into the selvage.
As a result, the weft thread ends are not reliably held in the selvage and when the fabric is subjected to its normal use the loops of the weft ends tend to let the weft ends be pulled out again of the fabric selvage. As a result, there is room for improvement in forming smooth tightly bound selvages along both fabric edges.
It has been further noted that the repeated shed formations of the warp threads actually help the unravelling or loop formations of the weft thread ends if the latter are not properly bound into the selvage. Thus, there is further room for improvement in avoiding an adverse effect of the shed formation on the binding of the weft thread ends in the selvage.